1. Field of the Invention
The present invention relates to an electronic timepiece, particularly to an electronic timepiece having a mechanism for reciprocating an indicator or the like using a step motor.
2. Background Information
Generally, according to an electronic timepiece mounted with a microcomputer, it is necessary to make an initial operating position of an IC logic circuit coincide with an initial portion of an indicator. As a position detecting mechanism therefore, there is provided a mechanism of a contact point system, a light detecting system, a pin system or the like.
In this case, the contact point system is a system of detecting a position by detecting a contact state between a portion of a gear for driving an indicator and a contact point portion normally brought into contact with the gear. Further, the light detecting system is a system of optically detecting an angular position of a gear or the like. As a conventional technology of the light detecting system, there is provided a technology disclosed in, for example, Japanese Patent Laid-Open No. 179058/1996.
The pin system is a system for realizing accurate positioning by bringing an indicator into contact with a pin for positioning. As a conventional technology of the pin system, there is provided a technology disclosed in, for example, Japanese Patent Laid-Open No. 291591/1987.
Meanwhile, according to a timepiece, there have been carried out not only pursuit of function as a time counting apparatus but also a devise of achieving a discrimination from other timepiece and promoting a value of a commercial product by adding a design as an ornamental article and a toy-like play feature. Particularly, at a current state realizing sufficiently high accuracy formation, price and added value constitute significant factors for a timepiece as a commercial product and there have been carried out various devises more than those at previous time. As an example of such a timepiece, there is known a constitution in which an indicator which has simply been rotated, is reciprocated in a predetermined range.
However, in the case of the example, when a hand is reciprocated only in a certain range, according to a conventional hand position detecting mechanism, there poses a problem of deteriorating durability, increasing cost, deteriorating detecting accuracy or increasing power consumption. Further, there poses a problem in which a troublesome operation of operation for correcting a positional shift (for example, operation of a winding crown) is requested to a user.
It is an object of the invention to provide an electronic timepiece capable of reciprocating a special indicator in a predetermined range, which is an electronic timepiece capable of correcting the reciprocating range without increasing the cost.
The invention has been carried out in order to achieve the above-described object and according to a first aspect of the invention, there is provided an electronic timepiece characterized in comprising an operating member supported in a reciprocatable state, a drive mechanism constituted by including a step motor to move the operating member by a respective predetermined amount in a desired regular or reverse direction in accordance with pulses inputted to the step motor, a restricting mechanism to mechanically restrict a range capable of moving the operating member (hereinafter, referred to as xe2x80x9cmovable rangexe2x80x9d), and controlling circuit to carry out a processing of reciprocating the operating member in a predetermined range and a correcting processing for correcting a shift in the range of reciprocating the operating member by inputting the pulses to the step motor, wherein in carrying out the correcting processing by the controlling circuit, the operating member is made to reach a distal end position of the movable range by inputting predetermined ones of the pulses to the step motor and thereafter, the number of pulses for moving the operating member in a direction of separating from the distal end position are inputted to the step motor.
Further, according to a second aspect of the invention, there is provided the electronic timepiece, characterized in that the number of the pulses inputted to the step motor to make the operating member reach the distal end position of the movable range, is a number by which an amount of moving the operating member becomes longer than the movable range.
Further, according to a third aspect of the invention, there is provided the electronic timepiece, characterized in that the controlling circuit carries out the correcting processing at predetermined intervals.
Further, according to a fourth aspect of the invention, there is provided the electronic timepiece, characterized in that the interval is prescribed based on time.
An explanation will be given of operation by the above-described aspects of the invention as follows. The operating member is supported in a reciprocatable state. However, the movable range is restricted by the restricting mechanism. Normally, the controlling circuit reciprocates the operating member in the predetermined range by inputting pulses to the step motor of the drive mechanism.
Further, the controlling circuit carries out the correcting processing for correcting the shift in the reciprocating range pertinently (for example, at predetermined intervals determined based on time or the like). The correcting processing is carried out by operating the operating member as follows by inputting the pulses to the step motor. That is, firstly, the operating member is made to reach the distal end position of the movable range. Thereafter, the operating member is moved in the direction of separating from the distal end position.
In this case, it is preferable that the number of the pulses inputted for making the operating member reach the distal end position of the movable range is the number by which the amount of moving the operating member in calculation is made to be longer than a width of the movable range.